Consider an ordinary truck with a vehicle frontal area of 22 square feet, a mass
ID: 2136761 • Letter: C
Question
Consider an ordinary truck with a vehicle frontal area of 22 square feet, a
mass of 1123 kg and an initial velocity of 40 mph is traveling up a long
sloping hill that rises in 3 miles from an elevation of 50 feet to 471 feet. The
final velocity of the car is 60 mph and the travel time for the 3 mile distance
is 235 seconds. Assume that the rolling resistance coefficient, Cr, for this
truck is 0.012 [1/sec].
a) Calculate the resisting drag force of the car if you consider average
acceleration and velocity values.
b) How much engine horsepower is used to overcome this resisting drag
force calculated above. For this calculation consider the average velocity of
the truck.
For this question I mostly just wasn't sure about the equation for rolling resistance force...
Explanation / Answer
)a=R/m -g
upwards a
v is upwards